I used various cheap rollers, but I think that Mimi is also a usable roller that is hard to come out. In our shop, we use 14 mm and 20 mm separately. It is regrettable that it will be a little cheaper if you buy a box. At the same time, mini small 4 inch box buying is too expensive, and we sell it in one store at a price of 13.650 yen per box at another shop. Hang in there!!